Japanese Patent Application Laid-open Publication No. 2012-185076 discloses a speed limit value notification device which is capable of using both a traffic sign detected from an image picked up by a vehicle-mounted cameral and a traffic sign acquired from map data stored in a map data storage section.
However, the speed limit value notification device disclosed in the No. 2012-185076 publication is constructed to merely determine whether or not the traffic sign based on the picked-up image and the traffic sign based on the map data agree with, or match, each other. Thus, when no traffic sign based on the picked-up image is detected, the speed limit value notification device disclosed in the No. 2012-185076 publication cannot determine a final traffic sign to be notified to an occupant of a vehicle. Namely, the inventors of the present invention etc. realized that, with the speed limit value notification device disclosed in the No. 2012-185076 publication, a probability or time period with or for which a final traffic sign can be notified to the vehicle occupant is low or short. The inventors of the present invention etc. realized that, in the case where a final traffic sign is determined with no traffic sign detected based on the picked-up image, a probability of an error existing in the final traffic sign to be notified the vehicle occupant should be lowered.